// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_PROXY_HOST_H_
#define CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_PROXY_HOST_H_

#include <stdint.h>

#include <memory>

#include "base/macros.h"
#include "content/browser/site_instance_impl.h"
#include "ipc/ipc_listener.h"
#include "ipc/ipc_sender.h"
#include "third_party/WebKit/public/platform/WebFocusType.h"

struct FrameHostMsg_OpenURL_Params;
struct FrameMsg_PostMessage_Params;

namespace content {

class CrossProcessFrameConnector;
class FrameTreeNode;
class RenderProcessHost;
class RenderViewHostImpl;
class RenderWidgetHostView;

// When a page's frames are rendered by multiple processes, each renderer has a
// full copy of the frame tree. It has full RenderFrames for the frames it is
// responsible for rendering and placeholder objects (i.e., RenderFrameProxies)
// for frames rendered by other processes.
//
// This class is the browser-side host object for the placeholder. Each node in
// the frame tree has a RenderFrameHost for the active SiteInstance and a set
// of RenderFrameProxyHost objects - one for all other SiteInstances with
// references to this frame. The proxies allow us to keep existing window
// references valid over cross-process navigations and route cross-site
// asynchronous JavaScript calls, such as postMessage.
//
// RenderFrameProxyHost is created whenever a cross-site
// navigation occurs and a reference to the frame navigating needs to be kept
// alive. A RenderFrameProxyHost and a RenderFrameHost for the same SiteInstance
// can exist at the same time, but only one will be "active" at a time.
// There are two cases where the two objects will coexist:
// * When navigating cross-process and there is already a RenderFrameProxyHost
// for the new SiteInstance. A pending RenderFrameHost is created, but it is
// not used until it commits. At that point, RenderFrameHostManager transitions
// the pending RenderFrameHost to the active one and deletes the proxy.
// * When navigating cross-process and the existing document has an unload
// event handler. When the new navigation commits, RenderFrameHostManager
// creates a RenderFrameProxyHost for the old SiteInstance and uses it going
// forward. It also instructs the RenderFrameHost to run the unload event
// handler and is kept alive for the duration. Once the event handling is
// complete, the RenderFrameHost is deleted.
class RenderFrameProxyHost
    : public IPC::Listener,
      public IPC::Sender {
public:
    static RenderFrameProxyHost* FromID(int process_id, int routing_id);

    RenderFrameProxyHost(SiteInstance* site_instance,
        RenderViewHostImpl* render_view_host,
        FrameTreeNode* frame_tree_node);
    ~RenderFrameProxyHost() override;

    RenderProcessHost* GetProcess()
    {
        return process_;
    }

    // Initializes the object and creates the RenderFrameProxy in the process
    // for the SiteInstance.
    bool InitRenderFrameProxy();

    int GetRoutingID()
    {
        return routing_id_;
    }

    SiteInstance* GetSiteInstance()
    {
        return site_instance_.get();
    }

    FrameTreeNode* frame_tree_node() const { return frame_tree_node_; };

    void SetChildRWHView(RenderWidgetHostView* view);

    RenderViewHostImpl* GetRenderViewHost();
    RenderWidgetHostView* GetRenderWidgetHostView();

    // IPC::Sender
    bool Send(IPC::Message* msg) override;

    // IPC::Listener
    bool OnMessageReceived(const IPC::Message& msg) override;

    CrossProcessFrameConnector* cross_process_frame_connector()
    {
        return cross_process_frame_connector_.get();
    }

    // Update the frame's opener in the renderer process in response to the
    // opener being modified (e.g., with window.open or being set to null) in
    // another renderer process.
    void UpdateOpener();

    // Set this proxy as the focused frame in the renderer process.  This is
    // called to replicate the focused frame when a frame in a different process
    // becomes focused.
    void SetFocusedFrame();

    void set_render_frame_proxy_created(bool created)
    {
        render_frame_proxy_created_ = created;
    }

    // Returns if the RenderFrameProxy for this host is alive.
    bool is_render_frame_proxy_live() { return render_frame_proxy_created_; }

private:
    // IPC Message handlers.
    void OnDetach();
    void OnOpenURL(const FrameHostMsg_OpenURL_Params& params);
    void OnRouteMessageEvent(const FrameMsg_PostMessage_Params& params);
    void OnDidChangeOpener(int32_t opener_routing_id);
    void OnAdvanceFocus(blink::WebFocusType type, int32_t source_routing_id);
    void OnFrameFocused();

    // This RenderFrameProxyHost's routing id.
    int routing_id_;

    // The SiteInstance this proxy is associated with.
    scoped_refptr<SiteInstance> site_instance_;

    // The renderer process this RenderFrameHostProxy is associated with. It is
    // equivalent to the result of site_instance_->GetProcess(), but that
    // method has the side effect of creating the process if it doesn't exist.
    // Cache a pointer to avoid unnecessary process creation.
    RenderProcessHost* process_;

    // The node in the frame tree where this proxy is located.
    FrameTreeNode* frame_tree_node_;

    // True if we have a live RenderFrameProxy for this host.
    bool render_frame_proxy_created_;

    // When a RenderFrameHost is in a different process from its parent in the
    // frame tree, this class connects its associated RenderWidgetHostView
    // to this RenderFrameProxyHost, which corresponds to the same frame in the
    // parent's renderer process.
    std::unique_ptr<CrossProcessFrameConnector> cross_process_frame_connector_;

    // The RenderViewHost that this RenderFrameProxyHost is associated with. It is
    // kept alive as long as any RenderFrameHosts or RenderFrameProxyHosts
    // are associated with it.
    RenderViewHostImpl* render_view_host_;

    DISALLOW_COPY_AND_ASSIGN(RenderFrameProxyHost);
};

} // namespace

#endif // CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_PROXY_HOST_H_
